While private data sessions generate separate work areas containing separate copies of a form's open tables, indexes, and relationships, every copy of the form references the same underlying base tables and base index files. When a user updates a record from one instance of a form, the base table referenced by the form is updated. You see the changes made from another instance of the form when you navigate to the changed record.

Locks taken on records or tables in one private data session are respected by other private data sessions. For example, if the user of data session 1 takes a lock on a record, the user in data session 2 cannot lock the record. If the user in session 1 opens a table exclusively, the user in data session 2 cannot open the table. By respecting locks taken by other data sessions, Visual FoxPro protects the integrity of updates to the underlying base tables.